pytest-ditto

Snapshot testing pytest plugin with minimal ceremony and flexible recorders.

📖 Documentation

Features

• Snapshot fixture — record test outputs once, assert they don't change
• Flexible recorders — strict JSON by default, built-in YAML, and external recorders for specialised data
• Remote backends — store snapshots locally, on S3, in PostgreSQL, Redis, DuckDB, or anywhere via fsspec
• Named profiles — reusable, named backend targets with isolated credentials
• CLI tools — list, update, prune, lint, and manage snapshots from the command line

Quick Start

pip install pytest-ditto

import ditto


def fn(x: int) -> int:
    return x + 1


def test_fn(snapshot) -> None:
    result = fn(1)
    assert result == snapshot(result, key="fn")

First run records the result. Subsequent runs assert it hasn't changed.

Recorders

Strict JSON accepts only exact built-in None, bool, int, finite float, str, list, and string-keyed dict values, recursively. Install external recorders explicitly for other data models. See the recorder and upgrading guides before migrating snapshots from pytest-ditto 1.x.

Documentation

Full documentation is available at owlowlyowl.github.io/pytest-ditto, including:

• Getting Started
• Guides (recorders, backends, custom plugins)
• CLI Reference
• API Reference

Examples

See examples/ for self-contained local, PostgreSQL, Redis, and DuckDB examples.